U.S. patent application number 11/170139 was filed with the patent office on 2006-01-05 for paper feeder for roll-shaped recording paper.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Katsuya Inana.
Application Number | 20060001729 11/170139 |
Document ID | / |
Family ID | 35513411 |
Filed Date | 2006-01-05 |
United States Patent
Application |
20060001729 |
Kind Code |
A1 |
Inana; Katsuya |
January 5, 2006 |
Paper feeder for roll-shaped recording paper
Abstract
Roll holders are respectively attached to both ends of a
recording paper roll. An edge index is rotatably attached to one of
the roll holders. The edge index is provided with an arrow-shaped
indicia and a high-reflection member. The edge index is set to a
rotational position where the indicia points a paper edge residing
at a circumferential surface of the recording-paper roll. Upon
setting the recording-paper roll to a printer, the high-reflection
member is detected by a photoelectronic sensor disposed in the
printer. By detecting the high-reflection member, it is possible to
find the rotational position of the paper edge of the
recording-paper roll.
Inventors: |
Inana; Katsuya; (Saitama,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
35513411 |
Appl. No.: |
11/170139 |
Filed: |
June 30, 2005 |
Current U.S.
Class: |
347/218 |
Current CPC
Class: |
B65H 2511/512 20130101;
B65H 2301/41369 20130101; B65H 19/126 20130101; B41J 15/042
20130101; B41J 11/0095 20130101; B65H 2220/02 20130101; B65H
2220/03 20130101; B65H 2220/03 20130101; B65H 2220/01 20130101;
B65H 2301/41346 20130101; B65H 2801/12 20130101; B65H 2511/512
20130101; B65H 2403/942 20130101; B65H 2511/212 20130101; B65H
2405/43 20130101; B41J 15/02 20130101; B65H 2511/212 20130101 |
Class at
Publication: |
347/218 |
International
Class: |
B41J 11/00 20060101
B41J011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2004 |
JP |
2004-197190 |
Claims
1. A paper feeder for a recording-paper roll in which a strip of a
recording paper is wound around a core in a roll form, said paper
feeder rotating said recording-paper roll in a feeding direction to
feed the recording paper, said paper feeder comprising: a
paper-feed roller coming into contact with a circumferential
surface of said recording-paper roll to rotate said recording-paper
roll; an edge-separating member disposed at a downstream side of
said paper-feed roller in the feeding direction of said
recording-paper roll, said edge-separating member peeling and
separating an edge of said recording paper, which resides at said
circumferential surface of said recording-paper roll, from said
recording-paper roll when said recording-paper roll is rotated in
the feeding direction; a pair of roll holders respectively attached
to both ends of said core so as to catch both sides of said
recording-paper roll, said roll holders rotating together with said
core; an edge-indexing member rotatably attached to an outer
surface of one of said roll holders, an index for pointing a
position of said edge being indicated on an outer surface of said
edge-indexing member, which is set such that said index points said
edge after setting said roll holder to said recording-paper roll; a
detector for detecting a rotational position of said edge-indexing
member while said recording-paper roll is rotated in a take-up
direction opposite to the feeding direction, said detector
outputting a detection signal in accordance with said rotational
position; and a controller for setting said edge of said recording
paper to an initial rotational position, which is located between
said paper-feed roller and said edge-separating member, on the
basis of said detection signal.
2. A paper feeder according to claim 1, wherein said edge-indexing
member is provided with an indicia being as said index, and an
object to be detected by said detector, said object to be detected
being fixed to a position related to said indicia.
3. A paper feeder according to claim 2, wherein said indicia has an
arrow shape whose direction points said edge of said recording
paper.
4. A paper feeder according to claim 2, wherein said object to be
detected is fixed to the position shifted by 180 degrees from said
indicia relative to the center of said edge-indexing member.
5. A paper feeder according to claim 4, wherein said object to be
detected is a high-reflection member having higher reflectance in
comparison with other portions of said edge-indexing member.
6. A paper feeder according to claim 5, wherein said detector for
detecting said object is a photoelectronic sensor.
7. A paper feeder according to claim 6, wherein said edge-indexing
member has a doughnut shape.
8. A paper feeder according to claim 1, further comprising: a pair
of plates for rotatably supporting the pair of said roll
holders.
9. A paper feeder according to claim 8, wherein said detector is
fixed to said plate rotatably supporting said roll holder to which
said edge-indexing member is attached.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a paper feeder for a
roll-shaped recording paper, which comprises a paper-feed roller
and an edge separator.
[0003] 2. Description of the Related Art
[0004] In a conventionally-known paper feeder, a recording-paper
roll is rotated in a feeding direction to advance a paper edge to a
paper feeding port. This paper feeder is disposed in a magazine to
which the recording-paper roll is set. Alternatively, the paper
feeder is disposed in a loading chamber to be loaded with the
recording-paper roll. After the recording-paper roll has been set,
an edge separating claw and a paper-feed roller come into contact
with a circumferential surface of the recording-paper roll at
positions having an interval in a circumferential direction. The
paper-feed roller rotates the recording-paper roll in the feeding
direction. The edge separating claw disposed at a downstream side
of the paper-feed roller in the feeding direction peels the paper
edge from the circumferential surface of the recording-paper roll
to conduct the paper edge to the paper feeding port. Therefore,
when the recording-paper roll has just been set, it is required to
position the paper edge at a rotational position between the edge
separating claw and the paper-feed roller.
[0005] In consideration of this, the printer described in Japanese
Patent Laid-Open Publication No. 2000-169013 comprises an edge
detecting mechanism for automatically detecting the edge of the
recording-paper roll. This edge detecting mechanism rotates the
recording-paper roll in a take-up direction to detect the edge
during the rotation thereof. The edge detecting mechanism comprises
a base roller for abutting on the circumferential surface of the
recording-paper roll, an actuator lever for rotating around the
base roller, a driven roller attached to a halfway portion of the
actuator lever, a first spring for urging the actuator lever so as
to make the driven roller abut on the circumferential surface of
the recording-paper roll, and a switch for outputting a detection
signal. The switch outputs the detection signal in association with
a movement of the actuator lever when the driven roller has passed
the edge during a reverse rotation of the recording-paper roll.
[0006] As described above, the edge detecting mechanism includes
the driven roller for abutting on the circumferential surface of
the recording-paper roll. In this mechanism, the movement of the
driven roller having passed the edge is detected by a detector.
This kind of the mechanism is also employed for a printer described
in Japanese Patent Laid-Open Publication No. 2002-179308.
[0007] The above edge detecting mechanism rotates the
recording-paper roll in the take-up direction to automatically
detect the rotational position of the edge in the circumferential
direction of the recording-paper roll. Thus, an operation is simple
at the time of setting of the recording-paper roll. However, since
the edge detecting mechanism needs many parts of the rollers, the
detector and so forth besides the paper-feed roller and the edge
separating claw, a structure thereof becomes complicated and a lot
of trouble is taken in an assembly operation. Moreover, the cost of
the entire apparatus increases because of the large number of the
parts. Meanwhile, the edge detecting mechanism has a small size for
the purpose of detecting the edge of the recording-paper roll.
Thus, when setting the recording-paper roll, the edge detecting
mechanism is likely to be broken or damaged if the recording-paper
roll hits this mechanism due to a setting attitude thereof.
Further, the edge detecting mechanism is likely to malfunction due
to an effect of paper dust collected during long-term use, and due
to deterioration of the spring.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing, it is a primary object of the
present invention to provide a low-cost paper feeder in which it is
possible to surely detect a rotational position of a paper edge of
a recording-paper roll.
[0009] In order to achieve the above and other objects, the paper
feeder according to the present invention comprises a pair of roll
holders, an edge-indexing member, a detector and a controller. The
roll holders are respectively attached to both ends of a core of a
recording-paper roll so as to catch the recording-paper roll. The
roll holders rotate together with the core. The edge-indexing
member is rotatably attached to an outer surface of one of the roll
holders. An indicia for pointing a position of the paper edge is
indicated on the edge-indexing member. After setting the roll
holder to the recording-paper roll, the edge-indexing member is
attached to the roll holder so as to point the paper edge with the
indicia. While the recording-paper roll is rotated in a take-up
direction, the detector detects a rotational position of the
edge-indexing member to send a detection signal in accordance with
the rotational position. On the basis of the detection signal, the
controller sets the recording-paper roll to an initial rotational
position.
[0010] Incidentally, the edge-indexing member may be provided with
the indicia and an object to be detected by the detector. The
object to be detected is fixed to a position related to the
indicia. It is needless to say that the indicia itself may be
detected by the detector.
[0011] In the paper feeder according to the present invention, the
edge-indexing member attached to one of the roll holders is set
such that the indicia points the paper edge. The rotational
position of the edge-indexing member is detected by the detector.
Thus, it is possible to easily find the edge position of the
recoding-paper roll. Moreover, it is possible to manufacture the
paper feeder at low cost, since a number of parts is reduced in
comparison with a conventional paper-edge detecting mechanism.
Further, since the detector detects the rotational position of the
edge-indexing member from the side of the roll holder, damage and
so forth are hardly caused and the detection of the rotational
position is surely performed for a longer time in comparison with a
conventional mechanism in which a detector is disposed on a
circumferential surface of the recording-paper roll.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above objects and advantages of the present invention
will become apparent from the following detailed description of the
preferred embodiments of the invention when read in conjunction
with the accompanying drawings, in which:
[0013] FIG. 1 is a perspective view partially showing a printer
using a paper feeder according to the present invention;
[0014] FIG. 2 is an exploded perspective showing a recording-paper
roll unit;
[0015] FIG. 3 is a partial perspective view of the printer showing
a loading chamber of the printer;
[0016] FIG. 4 is an explanatory illustration showing the loading
chamber loaded with the recording-paper roll unit;
[0017] FIG. 5 is a schematic section view showing a sensor disposed
in the loading chamber;
[0018] FIG. 6 is an explanatory illustration schematically showing
an electrical structure of the printer; and
[0019] FIG. 7 is an explanatory illustration showing the loading
chamber in which the recording-paper roll is set to an initial
rotational position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0020] As shown in FIG. 1, a printer 10 using a paper feeder
according to the present invention has a loading lid 11 provided at
a lateral side thereof. The loading lid 11 is slidable in a drawing
direction. When the loading lid 11 is drawn, a loading chamber 12
is exposed from the inside. A recording-paper roll unit 13 is
removably loaded in the loading chamber 12.
[0021] As shown in FIG. 2, the recording-paper roll unit 13
comprises a recording-paper roll 14 and a pair of roll holders 15
and 16. The recording-paper roll 14 is formed such that a strip of
a recording paper 18 is wound around a core 17 of a hollow
cylindrical shape. Incidentally, an edge 18a of the new
recording-paper roll 14 is secured with a tape 9.
[0022] A code 19 representing management information of the
recording paper 18 is recorded on one end of the core 17. The code
19 represents the information concerning a sort of the recording
paper, a manufacturer, manufacture information and an
identification number. Further, the code 19 also represents the
information concerning thermal sensitivity when the recording paper
is a thermosensitive recording paper. For example, the code 19 is
formed in a bar-code style wherein a low-reflection region and a
high-reflection region are combined. The low-reflection region
includes a quiet zone and a black bar. The high-reflection region
is a white bar. By the way, the code is not limited to the bar-code
style, and may have a circular-shape style. In this case, the code
is formed such that the inside of the circular area corresponds to
the white bar of the high-reflection region and the outside of the
circular area corresponds to the black bar of the low-reflection
region.
[0023] The roll holders 15 and 16 comprise flanges 20 and 21,
shafts 22 and 23, and core shafts 24 and 25. The flanges 20 and 21
catch both ends of the recording-paper roll 14 to position the
recording paper 18 in a width direction thereof. The core shafts
24, 25 and the shafts 22, 23 are respectively formed so as to
straightly protrude in opposite directions at both sides of the
flanges 24 and 25. The core shafts 24 and 25 are fitted into the
core 17 of the recording-paper roll 14. The shafts 22 and 23 are
rotatably attached to bearings disposed at the loading chamber 12.
The core shafts 24 and 25 are inserted into the core 17 to catch
both ends of the recording-paper roll 14 with the flanges 20 and
21. Thus, the roll holders 15 and 16 rotate together with
recording-paper roll 14.
[0024] The roll holder 15 is provided with an edge index 26 for
indicating a position of the edge 18a residing at the
circumferential surface of the recording-paper roll 14. The edge
index 26 is rotatable around the shaft 22 and is attached to the
opposite side to the inner side of the flange 20 coming into
contact with the end side of the recording-paper roll 18. The edge
index 26 has a dial-shaped circumference on which knurls are formed
for putting a finger. Further, a front side of the index 26 is
provided with an arrow-shaped indicia 28 and a high-reflection
member 29. The edge index 26 is set to a rotational position where
an arrow direction of the indicia 28 is adjusted to the edge 18a
residing at the circumferential surface of the recording-paper roll
14. The high-reflection member 29 is disposed at a position shifted
by a predetermined angle, for example by 180 degrees, from the
indicia 28 relative to the shaft 22 (rotational center). The
high-reflection member 29 is formed from material having higher
reflectance in comparison with the other portion (low-reflection
portion). This material is a mirror seal, for instance. The
high-reflection member 29 is detected by a photoelectronic sensor
disposed at the loading chamber 12. Incidentally, it is desirable
to provide a ratchet stop and a click mechanism between the edge
index 26 and the roll holder 15 so that click feeling is obtained
every predetermined angle when the rotational position of the edge
index 26 is adjusted. Further, by the ratchet stop and the click
mechanism, the set position is prevented from being mistakenly
shifted.
[0025] As shown in FIG. 3, a pair of side plates 30 and 31 is
disposed in the loading chamber 12 so as to face each other in a
direction perpendicular to a drawing direction of the loading lid
11. The side plates 30 and 31 are respectively provided with guide
grooves 32 and 33 into which the shafts 22 and 23 of the roll
holders 15 and 16 are inserted. Bearings 34 and 35 are formed
downstream in a guiding direction of the guide grooves 32 and 33 to
guide the shafts 22 and 23. The pair of the bearings 34 and 35
rotatably supports the pair of the shafts 22 and 23 at a constant
position.
[0026] As shown in FIG. 4, the loading chamber 12 is provided with
a paper-feed roller 37, an edge separating claw 38 and a sensor
unit 39. The paper-feed roller 37 comes into contact with a
circumferential surface of the recording-paper roll 14 to rotate
this roll 14 in a paper-feed direction and a take-up direction. The
edge separating claw 38 is disposed at a downstream side of the
paper-feed roller 37 in the paper-feed direction of the
recording-paper roll 14 to peel and separate the edge 18a from the
recording-paper roll 14 rotating in the paper-feed direction. Drive
of the paper-feed roller 37 is inputted from the printer.
Incidentally, the paper-feed roller 37 and the edge separating claw
38 are adapted to approach the recording-paper roll 14 in
accordance with a change of a winding diameter thereof so as to
abut on the circumferential surface of the recording-paper roll
14.
[0027] The sensor unit 39 is attached to the side plate 30. The
sensor unit 39 is a unit component in which photoelectronic sensors
40 and 41 are unitized. The photoelectronic sensor 40 for detecting
the edge 18a senses the high-reflection member 29 and is disposed
at an orbit position of the high-reflection member 29 rotating
around the shaft 22 set to the bearing 34. The photoelectronic
sensor 41 for reading the code 19 is disposed at a rotational orbit
position of the end of the core 17 on which the code 19 is
recorded. The photoelectronic sensor 40 for detecting the edge 18a
is adapted to detect the high-reflection member 29 when the indicia
28 points an area extending between the paper-feed roller 37 and
the edge separating claw 38. Incidentally, the couple of the
photoelectronic sensors 41 and 40 are arranged along a line passing
the center of the shaft 22 set to the bearing 34 for the purpose of
unitization.
[0028] Each of the photoelectronic sensors 40 and 41 is a
reflective sensor having a light emitter and a light receiver. The
photoelectronic sensor 41 reads the code 19 while the
recording-paper roll 14 is rotated in the take-up direction. The
photoelectronic sensor 40 detects the high-reflection member 29
while the recording-paper roll 14 is rotated in the take-up
direction.
[0029] As shown in FIG. 5, the couple of the photoelectronic
sensors 40 and 41 are fixed to a block 43, which is attached to the
side plate 30. The photoelectronic sensor 40 for detecting the edge
18a is disposed so as to confront a surface 26a having the
high-reflection member 29. Meanwhile, the photoelectronic sensor 41
is disposed so as to confront the end 17a of the core 17 on which
the code 19 is recorded. Between the photoelectronic sensor 41 and
the end 17a, the roll holder 15 is located. In this embodiment, the
roll holder 15 is made of transparent material so that the code 19
is read out through the roll holder 15. If only the roll holder 15
to which the edge index 26 is fixed is made of the transparent
material, it is possible to prevent the roll holders 15 and 16 from
being mistakenly attached to both ends of the recording-paper roll
14. However, both of the roll holders 15 and 16 may be made of the
transparent material. By the way, the edge index 26 has a doughnut
shape so as not to disturb the detection of the photoelectronic
sensor 41 by its opening. Thus, it is unnecessary to form the edge
index 26 from the transparent material.
[0030] As shown in FIG. 6, a signal obtained from each of the
photoelectronic sensors 40 and 41 is sent to a printer controller
50, which controls a paper-feed motor 52 via a driver 51. Drive of
the paper-feed motor 52 is transmitted to the paper-feed roller 37
disposed in the loading chamber 12. Further, the printer controller
50 controls a printing unit 54 on the basis of the read code 19 to
record an optimum image. Incidentally, the printer controller 50
integrally controls the respective sections along a program read
from a ROM 55.
[0031] Next, an operation of the above structure is described
below. When assembling the recording-paper roll unit 13, the core
shafts 24 and 25 of the roll holders 15 and 16 are respectively
inserted into openings of both ends of the core 17. After
insertion, the edge index 26 attached to the roll holder 15 is set
to the rotational position where the indicia 28 points the edge 18a
of the recoding-paper roll 14. And then, the tape 9 securing the
edge 18a of the recording-paper roll 14 is peeled. Upon this, the
recording-paper roll unit 13 becomes available.
[0032] Successively, the loading lid 11 of the printer 10 is drawn
to expose the loading chamber 12. The recording-paper roll unit 13
is set, bringing the flanges 20 and 21 to the exposed loading
chamber 12. At this time, the shaft 22 of the roll holder 15 having
the edge index 26 is set to the bearing 34 of the pair of the
bearings 34 and 35 residing in the loading chamber 12. By doing so,
the recording-paper roll unit 13 is set in a state that the edge
18a is fed by rotating the paper-feed roller 37 in the paper-feed
direction.
[0033] Upon closing the loading lid 11, the paper-feed roller 37
and the edge separating claw 38 come into contact with the
circumferential surface of the recording-paper roll 14. After that,
it is detected whether there is or not the recording-paper roll
unit 13. When there is the roll unit 13, the printer controller 50
performs a print preparing operation in which the operation for
reading the code 19 is performed first, and then, the operation for
detecting the rotational position of the edge index 26 is
performed. After performing these operations, the printer 10 is
kept in a readiness state.
[0034] In the operation for reading the code 19, the paper-feed
motor 52 is driven to rotate the paper-feed roller 37 in the
take-up direction. At this time, the recording-paper roll 14 makes
at least one rotation. During this rotation, the photoelectronic
sensor 41 is monitored to read the code 19 on the basis of a
high-level signal and a low-level signal obtained from the
photoelectronic sensor 41.
[0035] After reading the code 19, the printer controller 50
continues rotating the paper-feed roller 37 in the take-up
direction to monitor the edge-detecting photoelectronic sensor 40
during this time. The photoelectronic sensor 40 detects the
high-reflection member 29. The printer processor 50 halts the drive
of the paper-feed motor 52 upon reception of a leading-edge signal,
which is obtained when the signal from the photoelectronic sensor
40 rises from the low level to the high level. Alternatively, the
printer controller 50 halts the drive of the paper-feed motor 52
after a predetermined period has passed from the reception of the
leading-edge signal. In virtue of this, as shown in FIG. 7, the
rotation of the recording-paper roll 14 is stopped at a position
where the high-reflection member 29 substantially overlaps with the
photoelectronic sensor 40 in a side viewing direction. At this
time, the edge 18a residing on the circumferential surface of the
recording-paper roll 14 is kept in an initial rotational position
located between the paper-feed roller 37 and the edge separating
claw 38. Hereby, the printer 10 is set in a print readiness state.
In this way, reading the code 19 and detecting the rotational
position of the edge index 26 are successively performed while the
paper-feed roller 37 is rotated in the take-up direction. Thus, the
print preparing operation is speedily performed.
[0036] The recording paper 18 of this embodiment is a well-known
color thermosensitive recoding paper in which cyan, magenta and
yellow thermosensitive coloring layers are formed on a support in
order.
[0037] The printing unit 54 includes a carrying roller pair, a
thermal head and an optical fixing unit and so forth. The carrying
roller pair nips the edge 18a of the recording paper 18 and carries
it in the printing unit 54. The thermal head performs thermal
recording for the respective thermosensitive coloring layers of the
recording paper 18. The optical fixing unit optically fixes the
respective thermosensitive coloring layers, for which thermal
recording has been performed, by applying ultraviolet rays.
[0038] Upon a print instruction, the printer controller 50 drives
the paper-feed motor 52 and reverses the paper-feed roller 37 to
rotate the recording-paper roll 14 in the paper-feed direction.
Hereby, the edge 18a is separated from the roll 14 by means of the
edge separating claw 38, and the edge 18a is carried toward a paper
slot 60. Then, the recording paper 18 is fed to the printing unit
54. The fed recording paper 18 is carried by the carrying roller
pair in the printing unit 54 to pass the thermal head and the
optical fixing unit in order. During this time, print processing is
performed in a three-color frame sequential manner to record a
full-color image. The processed recording paper 18, for which the
print processing has been performed, is cut by a cutter into a
predetermined size. The cut recording paper 18 is discharged to the
outside of the printer 10. Meanwhile, the recording paper 18 from
which the image-recoded paper is separated is rewound into the
loading chamber 12 by reversing the paper-feed roller 37.
[0039] The printing unit 54 is provided with an edge detecting
sensor for detecting the edge 18a of the recording paper 18. At the
time of rewind of the recording paper 18, control is performed such
that the paper-feed motor 52 is driven for a predetermined period
after detecting the edge 18a with the edge detecting sensor. If the
paper-feed motor 52 is a pulse motor, control is performed such
that the paper-feed motor 52 is driven by a number of predetermined
pulses after detecting the edge 18a. In virtue of this control, the
recording-paper roll 14 is set again to the initial rotational
position where the edge 18a is located between the paper-feed
roller 37 and the edge separating claw 38.
[0040] In the printer 10, it is possible to designate a print
number at the time of print instruction. When the designated print
number is two or more, print processing is successively performed
by times of the designated number. After completing the successive
processing, the recording paper 18 is rewound.
[0041] With respect to the recording paper 18, there are some kinds
having different widths. When the recording paper 18 is exchanged
to another one having a different width, the loading lid 12 is
drawn to remove the recording-paper roll unit 13. Further, the
couple of the roll holders 15 and 16 are detached from the
recording-paper roll unit 13. And then, the detached roll holders
15 and 16 are attached to the new recoding-paper roll 14, and the
rotational position of the edge index 26 is set. In this way, the
rotational position of the edge index 26 is set whenever the
recording-paper roll unit 13 is placed. Owing to this, it is
possible to surely and easily detect the edge 18a of the recording
paper roll 14.
[0042] In the above embodiment, the recording-paper roll 14 having
the paper information is used. The present information, however, is
not limited to this. It is possible to use the recording-paper roll
having no paper information. In this case, the photoelectronic
sensor 41 may be omitted. Moreover, in this case, it is unnecessary
to form the roll holder 15 from the transparent material.
[0043] In the above embodiment, the edge index 26 is provided with
the indicia 28 and the high-reflection member 29. The present
invention, however, is not limited to this. The indicia 28 may be
detected as the high-reflection member by the photoelectronic
sensor 40. Moreover, the high-reflection member 29 disposed on the
surface 26a of the edge index 26 is detected by the photoelectronic
sensor 40 of which the light emitter faces the surface 26a.
However, the high-reflection member may be disposed on a
circumferential surface of the edge index 26, and the light emitter
of the photoelectronic sensor may point in a diameter direction to
detect the high-reflection member. Further, the photoelectronic
sensor is not exclusive as the detecting member. A proximity switch
may be used. In this case, a metal member is disposed on the edge
index 26 instead of the high-reflection member. In the above
embodiments, detection is performed in the non-contact manner.
However, contact-type detecting members comprising a projection and
a microswitch may be used.
[0044] The above embodiment relates to the stationary type in which
a rotational axis of the recording-paper roll 14 is rotatably kept
in the constant position. However, this is not exclusive. It is
possible to adopt a moving type in which the shafts 22 and 23 of
the recording-paper roll unit 13 move toward the paper-feed roller
37 in accordance with the change of the winding diameter of the
recoding-paper roll 14. In this case, the photoelectronic sensors
40 and 41 are moved in association with the movement of the shafts
22 and 23 of the recording-paper roll unit 13 in the same direction
and at the same speed.
[0045] In the above embodiment, the recording-paper roll 14 is
rotated in the paper-feed direction and the take-up direction by
rotating the paper-feed roller 37 forward and backward. However,
only when the recording paper is taken up, drive may be inputted
into the roll holder from the printer to rotate the recording-paper
roll 14 in the take-up direction.
[0046] Although the present invention has been fully described by
way of the preferred embodiments thereof with reference to the
accompanying drawings, various changes and modifications will be
apparent to those having skill in this field. Therefore, unless
otherwise these changes and modifications depart from the scope of
the present invention, they should be construed as included
therein.
* * * * *